1. Field of the Invention
The present invention relates to a control apparatus, more particularly to a control apparatus, which includes a fluid passage for cooling purpose.
2. Description of Related Art
In general, a control apparatus includes a board, on which heat generating on-board devices are installed to form a control circuit arrangement. Thus, the heat generated from the on-board devices should be released effectively from the on-board devices and the board. For example, Japanese Unexamined Patent Publication No. 11-257483 discloses one technique for releasing the heat from the on-board devices and the board.
In the case of the invention recited in Japanese Unexamined Patent Publication No. 11-257483, the oil, which has the temperature lower than that of the surrounding of the control circuit arrangement, flows through an oil passage formed in a body. In this way, the heat is released from the on-board devices and the board to the oil, which flows in the oil passage, through a plate.
With respect to the above control apparatus, it has been demanded to downsize the control circuit arrangement. To meet the demand, the packaging density of the control circuit arrangement has been increased. Therefore, the amount of heat released from the on-board devices of the control circuit arrangement, which includes a power device for controlling, for example, a power source, is increased. As a result, effective heat release from the on-board devices and the board is required.